The present invention is in the area of packet routers for use with wide-area packet networks, such as the Internet, and pertains more particularly to Link State Routing Protocol(LSRP) for such routers and networks.
At the time of the present patent application demand for increased data capacity and efficiency in Internet traffic continues to increase dramatically as more individuals and businesses increase their use of the Internet. The ever-increasing demand also drives development of equipment for the Internet such as data packet routers. A number of enterprises are developing routers that are capable of faster and higher capacity handling of data packets.
The Internet, operating globally, comprises components from a wide variety of companies and organizations. It is, of course, necessary that such equipment conform to certain hardware and connection standards and operate by certain data transfer standards and protocols. These standards are all well known to the skilled artisan.
As new and better equipment for routing data traffic in the Internet continues to be developed, researchers developing such equipment are including fault tolerance, diagnostic capabilities, and redundancy into the equipment, links between instances of routing equipment, and in routing protocols.
One of the important developments in Internet technology as of the time of filing of the present patent application is in development of faster, and scalable routers. The present inventors, for example, are involved in development of what are known in the art as Terabit routers, capable of much higher packet transfer rates than currently available in the art. These routers are scalable to higher and higher overall data transfer rates, by allowing upwards of seven thousand interfaces to network traffic.
As the number of interfaces to network traffic grows, the importance of scalability and fault-tolerance grows apace. What is clearly needed is a method for making link-state routing protocols both scalable and fault. tolerant.
In a preferred embodiment a distributed Link-State Routing Protocol (LSRP) system in a packet switch having external communication ports is provided, comprising a first card executing an update process of the LSRP, making database updates, a second card executing Decision (Shortest Path First (SPF)) process of the LSRP, and a communication fabric coupling the cards with each other and the external ports. In some embodiments the LSRP is one of an Intermediate System to Intermediate System (IS-IS) LSRP, and in others an Open Shortest Path First (OSPF) LSRP. Also in some embodiments there may be a third card communicating through the fabric with the first and second cards and the ports, wherein the first card updates both the second and third cards, maintaining synchronized copies of the Link State, Adjacency, and Circuit databases.
In some embodiments there is also a location service (LS) controller operating external to the LSRP-related processes on the cards, wherein the LS controller configures and monitors the LSRP system. The LS controller may configure one of the three cards to execute the LSRP Update process, another to execute the LSRP Decision process, and the third to act as a backup, and may reassign roles according to monitored condition of the three cards.
In another aspect of the invention a distributed Link-State Routing Protocol (LSRP) system in a packet switch having external communication ports is provided, comprising a set of two or more cards in communication with one another and with the external communication ports, and a location service (LS) controller separate from but in communication with the cards. In this system the LS controller monitors and configures the cards, assigning LSRP functions and backup functions to individual cards.
In some embodiments of the system the LS controller reassigns functions to cards in the system in response to failures of cards in the system, providing fault tolerance.
In still another aspect of the invention a method for distributing a Link-State Routing Protocol in a packet switch having more than a single card is provided, comprising the steps of (a) configuring a first card to execute update process of the protocol; (b) configuring a second card to execute Decision process(Shortest-Path First (SPF)) of the protocol; and (c) executing the configured functions on the cards, and synchronizing copies of a the Adjacency, Circuit, and Link State databases on the cards.
In some embodiments of the method the LSRP is one of an Intermediate System to Intermediate System (IS-IS) LSRP or an Open Shortest Path First LSRP. There may further be a location service (LS) controller operating external to the card executing LSRP process, wherein the LS controller configures and monitors the LSRP system.
In some embodiments of the method there is at least a third card, wherein the LS controller configures one of the three to execute the LSRP Update process, another to execute the LSRP Decision(SPF) process, and the third to act as a backup, and reassigns roles according to monitored condition of the three cards. Two or more cards may be configured to execute the Update functions of the protocol.
In various embodiments of the invention described in enabling detail below, for the first time a scalable and fault tolerant Link State Routing Protocol is provided.